A finishing efficiency improvement of hardened steel has not been achieved because the tool life is reduced due to significant progress in tool wear and the occurrence of tool chipping. Therefore, a machining efficiency improvement is desired. In previous research, a machining efficiency improvement of 3 to 5 times can be achieved by increasing the feed rate in the finish machining of hardened steel by driven rotary machining. The cutting atmosphere affects the oxidation control of the film, and thus micro dry ice powder is applied to the cutting edge. To increase machining efficiency, the feed rate and cutting velocity must be increased, but this would shorten of tool life by increasing the cutting temperature. Therefore, it is essential to improve both the atmosphere and the oxidation resistance of the tool coating. In this study, the effect of coated tools with different Al contents on cutting performance was investigated for high-efficiency machining by high-speed cutting. At a high cutting velocity (3.34 m/s), the coated tool with the highest Al content had the longest tool life. It was found that high-efficiency cutting is possible even with a high-cutting velocity by increasing in the Al content of the coating.